Won’t rev

[cadetchris]

So my minor won’t rev.
If I floor the throttle, nothing happens for a while just the engine continues to idle and then slowly the revs pick up and all is normal.
If I lift the carb piston a bit (either with the plunger or my finger) then it revs normally, but when I look down the throat of the carb, the piston is flat against the bottom of the carb.

I have replaced the float and the float needle, the pump is working fine and I have blown through the fuel pipe as I originally thought it may be blocked.

Any ideas?

[JOWETTJAVELIN]

If the piston won’t rise through natural induction, it is catching against something. Start by centring the jet. With the engine off, and the carb oil cap removed, the piston should be able to be lifted and then fall down again smartly.

[kevin s]

If you decide to clean the dashpot/ piston don't use anything abrasive, they are machined to a very fine tolerance, clean it all up with carb cleaner, usually it's just deposits of old oil and carbon from the breather system which gums them up.

[cadetchris]

Well I went for the sledgehammer solution and replaced the jet and needle in the carb, then after a suggestion about the weights in dizzy, I replaced the whole dizzy with a new electronic one. Safe to say that the car purrs like a kitten